OSCAR: Combination antihypertensives in elderly most effective in those with CVD
MedWire News: Elderly hypertensive patients with pre-existing cardiovascular disease (CVD) derive the most benefit from treatment with a combination of an angiotensin II receptor blocker (ARB) and a calcium channel blocker (CCB), show results from the OSCAR study.
Conversely, elderly patients with Type 2 diabetes but no prior CVD had a nonsignificantly lower rate of the primary endpoint (combination of fatal and nonfatal CVD events and all-cause death) with high-dose ARB monotherapy than with combination ARB and CCB therapy.
But elderly hypertensive patients without prior CVD or diabetes had a similar rate of CVD events and death whether treated with combination therapy or high-dose ARB alone.
"The OSCAR study provides the first evidence showing that a standard dose of ARB plus CCB combination is superior to high-dose ARB treatment in reducing adverse events in elderly hypertensive patients with CVD," said lead investigator Hisao Ogawa from Kumamoto University in Japan. "However, high-dose ARB better prevented adverse events in diabetic patients in spite of its weaker antihypertensive effect."
The OlmeSartan and Calcium Antagonists Randomized (OSCAR) study enrolled 1164 high-risk elderly hypertensive patients, aged 73.6 years on average, from 134 centers throughout Japan between June 2005 and May 2007. Of these, 578 were given a high-dose ARB (olmesartan 40 mg/day) and 586 were assigned to take combination ARB/CCB therapy (olmesartan 20 mg; azelnidipine or amlodipine).
The patients were followed-up at 36 months for incidence of the primary endpoint, as well as degree of blood pressure change. Overall, the primary endpoint occurred at a similar rate in both treatment groups, but patients with prior CVD (n=812) had a significantly higher rate of the primary endpoint with monotherapy than with combination therapy, at 51 versus 34 events (hazard ratio [HR]=1.63; p=0.0261). Conversely, patients with Type 2 diabetes (n=628) had a nonsignificantly lower event rate with monotherapy, at seven events, than with combination therapy, at 14 events (HR=0.54; p=0.145).
Blood pressure reduction was adequately controlled in both treatment groups at 36 months, but combination therapy resulted in 2.4 mmHg lower systolic and 1.7 mmHg lower diastolic blood pressure compared with monotherapy (p=0.0315 and 0.0240, respectively). However, this did not appear to effect the incidence of the primary endpoint.
"The CASE-J trial supported the idea that ARBs and CCBs are both beneficial as first-line agents for the treatment of hypertension in elderly patients," said Ogawa.
"However, our research team did not know of any studies comparing the efficacy of high-dose ARB monotherapy with standard-dose combination therapy in terms of preventing cardiovascular morbidity and mortality in elderly patients. Thus, the OSCAR study may have a significant impact on determining the best antihypertensive therapeutic strategy for these patients."
Ogawa presented the findings at the American College of Cardiology Annual Scientific Sessions in New Orleans, Louisiana, USA.
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By Helen Albert